1. Technical Field
This invention relates to a device for facilitating the extraction of an implanted medical apparatus from the body of a patient. More particularly, the invention relates to a device for preparing an implanted elongated medical apparatus for extraction from a body passageway by exerting a compressive force along the proximal end of the elongated apparatus to hold the elements of the apparatus in place during the extraction procedure.
2. Background Information
A variety of medical treatments and surgical methods entail implanting a device, such as a pacemaker, in the body of a patient. A pacemaker is typically positioned in a subcutaneous tissue pocket in the chest wall of a patient. A pacemaker lead is implanted in the body of the patient to extend from the pacemaker through a vein into a chamber of the patient's heart. The lead comprises an elongated apparatus that includes one or more longitudinal cables, wires, coils, etc. (hereafter collectively referred to as “cables”) encased within an elongated insulating body along the length of the lead. Some cables may conduct electrical signals (such as stimulating and/or sensing signals) between the pacemaker and the heart. Other cables may provide strength and/or support to the lead. The cables may extend the entire length of the lead, or a segment of that length. The elongated insulating body, generally formed of silicone or a polymer such as polyurethane, serves to simultaneously protect the cables from body fluids, and insulate the cables from one another.
A defibrillator is another example of a cardiac device that utilizes implanted elongated leads to transmit electrical signals from the defibrillator to the heart. Leads for defibrillators are generally similar to pacemaker leads, and may be affixed either internally or externally of the heart. As used herein, a “cardiac lead” may refer to either a pacemaker lead or a defibrillator lead.
While an implanted apparatus, such as a cardiac lead, may have a useful life of many years, at some point consideration may be given to extracting the lead. However, over time such leads may have become encapsulated by fibrotic tissue against the heart itself or the wall of the vein, or against other surrounding tissue. Encapsulation is especially encountered in areas where the velocity of the flow of blood is low. The fibrotic tissue can be very tough, which makes it difficult to remove the lead from the area of the heart without causing trauma to the area. When small diameter veins through which a cardiac lead passes become occluded with fibrotic tissue, separation of the lead from the vein can cause severe damage to the vein, including the possible dissection or perforation of the vein. In such cases, separation of the lead from the vein is usually not possible without restricting or containing movement of the lead, i.e., fixing the lead in position with respect to the patient, in particular, with respect to the patient's vein.
To avoid this and other possible complications, some useless cardiac leads are simply left in the patient when the pacemaker or defibrillator is removed or replaced. However, this practice can incur the risk of an undetected lead thrombosis, which can result in stroke, heart attack, or pulmonary embolism. The practice can also impair heart function, since plural leads can restrict the heart valves through which they pass. Other potential risks include obstruction of fluid flow through the vein by the inoperable lead, and migration of the lead such that it may interfere with the pacing or defibrillating function. Finally, the presence of an inoperable lead may also contribute to undesirable conditions such as septicemia or endocarditis.
Surgical removal of a cardiac lead in such circumstances often involves open heart surgery. However, open heart surgery is accompanied by significant risk and cost to the patient, as well as a potential for unintended complications. A variety of methods and apparatuses have been devised for use as alternatives to open heart surgery for cardiac lead removal. Several of these methods and apparatuses are described in related patent documents, such as U.S. Pat. No. 5,697,936, titled “Device for Removing an Elongated Structure Implanted in Biological Tissue”; U.S. Pat. No. 5,507,751, titled “Locally Flexible Dilator Sheath”; U.S. Pat. No. 5,632,749, titled “Apparatus for Removing an Elongated Structure Implanted in Biological Tissue”; U.S. Pat. No. 5,207,683, titled “Apparatus for Removing an Elongated Structure Implanted in Biological Tissue”; U.S. Pat. No. 4,943,289, titled “Apparatus for Removing an Elongated Structure Implanted in Biological Tissue”; U.S. Pat. No. 5,011,482, titled “Apparatus for Removing an Elongated Structure Implanted in Biological Tissue”; U.S. Pat. No. 5,013,310, titled “Method and Apparatus for Removing an Implanted Pacemaker Lead”; U.S. Pat. No. 4,988,347, titled “Method and Apparatus for Separating a Coiled Structure from Biological Tissue”; U.S. Pat. No. 5,423,806, titled “Laser Extractor for an Implanted Object”; U.S. Pat. No. 6,136,005, titled “Apparatus for Removing a Coiled Structure Implanted in Biological Tissue, Having Expandable Means including a Laterally Deflectable Member”; U.S. Pat. No. 6,419,974, titled “Radio Frequency Dilator Sheath”, U.S. Pat. No. 6,687,548, titled “Apparatus for Removing an Elongated Structure Implanted in Biological Tissue”; U.S. Pat. No. 6,712,826, titled “Apparatus for Removing an Elongated Structure Implanted in Biological Tissue”; U.S. Pat. No. 7,359,756, titled “Apparatus for removing an Elongated Structure implanted in Biological Tissue”; U.S. Pat. No. 7,651,504, titled “Device for Removing an Elongated Structure Implanted in Biological Tissue”; U.S. Pat. No. 8,192,430, titled “Device for Extracting an Elongated Structure Implanted in Biological Tissue; U.S. Pat. Publ. No. 2005/0192591, titled “Device for removing an Elongated Structure Implanted in Biological Tissue”; U.S. Pat. Publ. No. 2006/0235431, titled “Lead Extraction Device”; U.S. Pat. Publ. No. 2010/0222787, titled “Tension Control Device”; and U.S. Pat. Publ. No. 2011/0238078, titled “Device and Method for Positioning an Implanted Structure to Facilitate Removal”, among others. Each of the aforementioned patents and publications is incorporated by reference as if fully set forth herein.
Although the prior art devices have been found to be reasonably effective in many situations, physicians continue to encounter problematic situations in which existing extraction devices may not perform as efficiently as desired for lead removal, and/or in which the capability of the device to remove the lead could be enhanced by preparing the lead for removal prior to entry of the extraction device into the body passageway.
One such instance involves the removal of an implanted apparatus, such as a cardiac lead as described above having one or more cables, etc., extending along a length of the apparatus. After such apparatuses have been implanted for a period of time, the cables can work their way through the insulating material, such that they extend outwardly, or laterally, of the main body of the implanted apparatus along this length. This arrangement may hamper the ability of the physician to advance an extraction device over the proximal end of the implanted apparatus, as the laterally extending cable may be positioned in a manner such that it is not easily captured within the extraction device as that device tracks along the outer surface of the apparatus.
It would be desirable to provide a device that is capable of arranging the proximal end of the implanted apparatus in a manner to facilitate advancement of an extraction device thereover, and to facilitate extraction of the implanted apparatus from encapsulating tissue in the body passageway.